3-part foam construction relieves pressure and prevents bottoming out. - Firm foam base fused to a middle layer of high-density polyurethane foam for comfort and stability - Top layer of ultra visco elastic memory foam offers hugely improved pressure reduction and relief - Supplied with Harley Premium Dartex waterproof / VP cover - welded seams, anti slip base - Other options available. Suitable patients up to high risk (with appropriate nursing care).